Automatic emergency keyer unit



C. E. SUNDERLAND AUTOMA Dec. 2, 1952 TIC EMERGENCY KEYER UNIT Filed July 5, 195o IN VENT 0R.

CHH/ELES E. Jl//V EKL/)ND BY TOE/VEYS Patented Dec. 2, 1,1952

oFFIcE f i AUTOMATIC EMERGENCY KEYER UNIT charles E. Sunderland, Mobile, Ala. Application July 3, 1950, Serial No. 171,998

Claims. (Cl. 177-380) (Granted under the act of March.3, 1883, as

amended April 30, 1928; 370 0. G. 757) The-1nvention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to ie of any royalty thereon.

This invention relates to a device for automatically keying a distress signal by way of the radio transmitter of an aircraft.

It frequently happens that the pilot of an aircraft, in distress, delays sending out an SOS in the'hope that the trouble may be righted and acrash avoided. Usually when he does decide that a crash cannot be avoided it is either too late to key out a distress call manually, or the craft may be pitching and rolling to such an extent as to make manipulation of the conventional hand key impossible.-

`The embodiment of the invention 'herein shown and described is so constructed and arranged that a distress call is automatically sent out upon a preset drop in altitude whether or not the pilot desires it.

After a predetermined series of distress calls comprising alternate SOS and ships identification calls, the dev-iceautomatically temporarily suspends these calls long enough to vsend between each series a prolonged buzz of about twenty seconds which may be used by such land stations as may pick up theA call to facilitate direction finding operations. Y i

Ihe altimeterherein shown as part of the invention may be one especially constructed for the purpose disclosed, or the altimeter already on the aircraft may, with slight modication, be adapted for use without interference with its normal function.

Also, the radio transmitter through which the distress message is to be sent is the one already provided on the plane with no change further than the wiring for electrically connecting the old and the new g-instrumentalities.

' The single figure of the drawing is schematic only,V the several instrumentalities being spaced apart for clearness. It will be understood, however, that the several instruments may be arranged, assembled and electrically or otherwise connected in a fraction of the space as the assembly herein discloses.

, Referring now to the drawing, the altimeter In Vofan aircraft has a pointer I 2 which registers tbevheight in thousands of feet atwhich the craft is being own, lin the instant case this is nine thousand feet.

, A second pointer I4 is independently rotatable by a knob I5 andvwhen rotated clockwise will cause-the contact I8 on the pointer I4 to elec- 2 I trically engage the contact 20 on the pointer I2. In the drawing the pointer I4 is arbitrarily set at eight thousand feet whereby, when thealtimeter pointer I2 shows a drop of one thousand feet the contacts I8 and 20wil1 engage.

Engagement of contacts I8 and 20 allows low voltage current to flow from the D. C. source 22 through relay energizing coils 24 and 26 to ground, thereby closing relay switches 28 and 30 thus completing a circuit from the source 22 through a motor.32 and switch 28 to ground and from `the source 22 through a switch 30, bell 34 and light 3B to ground.

Upon starting of the motor 32, power is transmitted through pinions 38, 40 and 42 and gears 44, 46 and 48 to theV shaft 5l! upon which a main keying. cam 52 is rotatable. Main keying cam 52, around its periphery, is provided with a series of short'nodes 54 representing dots, and longer nodes 5B representing dashes of the International Code.

The automatic keying switch 58 consists of two insulatedly spaced apart fiexible blades 60 and 62 fastened as at 64 tol any suitable stationary portion of the device. Blade 60 has two ears 6I between which a small shaft 63 carries a roller 66 which is engaged by the nodes 54 and 56 to close the keying switch for dots and dashes. Blade E2 is grounded as shown.

Blade 60 is electrically connected to the low voltage source 22 through the relay coil 68 which operates the interrupter switch 'I0 of thev high voltage transmitter circuit in synchronism with the keying switch 58, and through the switch I2 which isin series with the coil E8. The switch 'I2 is closable by the coil I4 which gets current from .the low.voltage source 22. one end of the coil being grounded but only when the switch 28 is closed, whereby the keying relay may be operative onlywhen the altimeter contacts I8 and 2U are closed by the predetermined drop in altitude.

The transmitter on-and-oi relay comprises a switch 'I6 andits operating coil 18. The coill has one end connected to the low voltage supply irrespective of whether the altimeter contacts are open or closed and the other end is grounded. whereby the transmitter may be used for normal service without regard to altitude. The high voltage supply 82 is applied to the transmitter whenever the switch 'I6 closes. A manual switch 84 may be inserted in the low voltage line as shown.

55 -Attached to the gear 48 to rotate therewith is able on a stud 90. An auxiliary keying cam 92 is attached to the gear 88 to rotate therewith, the cam follower rod 94 being reciprocable in bear ings 96.

The small shaft `63 upon which the roller 66 rotates is prolonged to extend through an opening in the follower rod 94, whereby the blade [i may be'reciprocated-by the nodes 54, 56, or, at intervals corresponding to four or ve revolutions of the main cam 52, by the dwell lobe 91 on the auxiliary cam 92.

The device herein shown and described operates substantially as follows:

As soon as the pilot has reached the ialtitude at which he intends to ily, he sets the pointer I4 to an altitude somewhat lower than that of his intended flying course. If, due to some trouble, he starts to lose altitude, the lpointer Il2 will rotate anticlockwise until the contact 20 engages the contactl I8.

This will light the la-mp bulb 36, ring the bell 34 and start the motor 32 which rotates the automatic keying cam 52 upon which the short and long nodes 54 and 56 for international code dots and dashes alternately spell out an SOS, then the ships call letters, and, at intervals of four or ve revolutions of the cam 52 suspend the call and send out a twenty-second continuous signal which may be used by rescuing stations to get the direction of the ship or by several spaced apart stations to determine the ships location. The various instrumentalities above described may preferably be assembled and mounted in or on some sort of cabinet, panel, base orframe H as dictated by its position in the airplane.

Having 'described my invention, I claim:

1. An automatic emergency keying unit which comprises, in combination, an altimeter, two relatively movable electric contacts carried by said altimeter, means associated with said altimeter operated by a preset drop in .altitude to engage rsaid two electric contacts, a low voltage current source, a signal light, a signal bell, a motor and a keying switch, a motor operating relay and a signal operating relay both operative by closing of said contacts to 4direct an electric cur-V rent from said low voltage current source through electrical conducting means to said 'signal light, said signal bell, said motor vand 'said keying switch, a keying switch main cam in the form of a -rotatable disc having a plurality of short and long nodes adapted -upon rotation for opening 'and closing said keying switch .for dot-and-dash signals, yan auxiliary rotatable cam having one prolonged circumferentially extending node `adapted for holding said keying switch yclosed for a .pro--v longed uninterrupted signal, speed reducing gearing drivably connecting said Ymotor to said main camspeed reducing gearing driv-ably connecting said main cam to said auxiliary cam, a keying-` circuit-closing relay having one end of its `operating ycoil connected through conductors to the low voltage current source and lthe other end through conductors and thermotor relay switch to ground Whenever the motor 'relay switch is closed, said keying circuit closing relay being adapted when closed for connecting said keying switch through a keying switch circuit 'to said low voltage current source, a transmitter-circuitinterrupter relay having its operating coil connected in series with the keying switch circuit, a highvoltage current source, and a transmitter on-and-oi relay energizable from the :low voltage current :source to close and connect the high volage current source to the transmitter circu1 2. An automatic emergency keying unit which comprises an altimeter, two relatively movable electric contacts associated with said altimeter, means associated with said alti-meter operated by a preset drop in altitude to engage said two electric contacts,l a low vvoltage current source, a

, current source through electrical conducting means to said signal, said motor and said keying switch, a keying switch main cam in the form of a rotatable disc having a plurality of short and long nodes adapted upon rotation of said cam for opening and closing said keying switch for dot-and-dash signals, an auxiliary rotatable cam having one prolonged circumferentially extending node adapted for holding said keying switch closed for a prolonged uninterrupted signal, speed reducing gearing drivably connecting said motor to said main cam, speed reducing gearing drivably connecting said main cam` to said auxiliary cam, a keying-circuit-closing relay -having one end of its operating coil electrically connected to the low Voltage current sourceA and the other end through the motor relay switch to ground whenever the motor relay switch is closed, said keying circuit closing relay being adapted when closed` for connecting said keyingswitch through ua ,key-v ing switch circuit to said low voltage current source, a transmitter-circuit-interrupter relay having its operating coil connected in series with the keying switch circuit, a high voltage current source, and a transmitter on-and-o relay ener, gizable from the low voltage current sourcefto close andconnectthe high voltage current source to the transmitter circuit. p.

3. An automatic emergency keying unit which comprises, an altimeter, two relatively lmovable electric contacts, means associated YWith said altimeter operated by a preset drop in altitude to engage said two electric contacts, a low voltage current source,` a motor and -a keying switch. a motor operating relay operative by closing of said contacts to direct an [electric current from said low voltage current source to said motor and said keying switch, a keying switchrotatable lmain cam having a plurality of short and long .nodes adapted upon'roltation for opening .and closing said keying switch for dot-and-dash signals, ian auxiliary cam having one prolonged node :adapted for holding -said keying switch closed for an uninterrupted signal, speed reducing-gearing drivably connecting said motor to said main cam, speed reducing gearing drivably connecting 'sa-id maincam to said auxiliary cam, akeying-circuitclosing relay having one end of its operating coil electrically connected Ato thelow voltage current source and the other end thro-ugh the motor relay switch to Vground Whenever the motor rel-ay switch is closed, said keying circuit .closing relay being adapted when closed for electrically connecting said keying switch tosaid llovv voltage current source, a transmitterrcircuit 'interrup'ter relay having its operating coil-connected -in vseries' with the keying switch, ahigh voltage 'current saurce, and a transmitter o-n-and-off relay --energizable from the low voltage kcurrent source-to close and connect the high voltage current source to the transmitter circuit. v

4.l An emergency keying unit which comprises, relatively movable Ielec-:tric contacts, meansoper# atedby al drop in altitude to engage said electric contacts, a current source, a motor and a keying switch, both operative by closing 0f said contacts, a main cam having a plurality of nodes adapted for opening and closing said keying switch for dot-and-dash signals, an auxiliary cam having a prolonged node adapted for holding said keying switch closed for an uninterrupted signal, gearing drivably connecting said motor to said main cam, gearing drivably connecting said main cam to said auxiliary cam, means for connecting said keying switch -to said low voltage currentl source, a transrnitter-circuit interrupter relay having its operating coil connected in series with the keying switch, a high voltage current source, and a transmitter on-and-oif relay energizable from the low voltage current source to close and connect the high voltage current source to the transmitrter circuit.

5. In an emergency keying device, an altimeter having an altitude graduation and two pointers, one pointer movable along said graduation by Change in the altitude of said altimeter and the other pointer manually operable to indicate a lesser altitude, electrical contacts movable into means and a motor operable upon engagement l of said contacts, a main cam operable at a low engagement by said pointers, when both pointers point to the same altitude graduation, signalling CHARLES E. SUNDERLAND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,972,289 Chauveau Sept. 4, 1934 2,358,498 Espeseth l Sept. 19, 1944 2,389,786 Kohn Nov. 27, 1945 2,468,945 Sasser May 3, 1949y 2.500.809

Fennessy et al Mar. 14. 1950 

